The test browser keeps Chrome's default profile, disk cache included,
and nginx sends no Cache-Control header. Right after `npm run build` a
run could load the index.html of the previous build and test old code.
It showed up while measuring the scene view pan: a new debug hook
returned NaN although server and bundle already had it.
- signIn() turns the network cache off via
Network.setCacheDisabled before the first page load.
Tests:
- GM_STEPS=5 (fresh seed): ALL PASSED, 10 checks.
- ./check.sh: CHECK EXIT 0, 2080 tests.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>